When a scene is in apparent motion relative to an imaging device, collecting sufficient light to achieve a suitable dynamic range while preventing motion blur and artifacts can be difficult. In the case of satellite or airborne-based observation systems, this is a particular concern. A shorter exposure time may result in insufficient light exposure. Increasing the exposure time results in blurring. In a conventional satellite imaging system, this problem may be solved by increasing the effective aperture of the optics in order to collect more light during a given exposure time. But doing so increases both the size and weight of the optics, which greatly increases costs associated with satellite systems in particular.
Various conventional imaging systems address these concerns in various ways and with varying degrees of success. Some systems utilize linear sensors having elongated pixels or, alternatively, Time Domain Integration (TDI) sensors to compensate for apparent motion. These solutions require the imaging device to be aligned with the direction of apparent motion, and often require that the satellite system compensate for payload torques. In other imaging systems, mirrors, lenses, or the imaging sensors themselves are moved in the direction of travel in order to compensate for the direction of travel. Still other systems utilize computationally intensive solutions to compute motion and to direct the recording medium to move in order to compensate for motion.
In general, these systems are large and heavy, computationally intensive, complex, or all of the above.